The present invention relates generally to cooking utensiles having a body sheet of iron base metal with a non-stick coating on at least the food-contacting surfaces thereof, a procelain enamel coating being disposed between the non-stick coating and the body sheet of the cooking utensil to provide protection thereof in the event of a break in the non-stick coating.
There is disclosed in U.S. Pat. No. 3,008,601 granted Nov. 14, 1961 to M. Cahne a cooking utensile having a metallic base or body sheet to which was applied by fusion a polytetrafluoroethylene coating that was non-sticking with respect to foods and the like. Manufacturers of cooking utensils carrying such polytetrafluoroethylene coatings are well aware of the fact that such coatings are readily ruptured in use if metallic utensiles are applied to the coating, particularly if a knife edge or sharp fork tang is applied thereto, and thus recommend the use of wooden or plastic implements and utensils therewith. Further difficulties are sometimes encountered in maintaining adherence of the polytetrafluoroethylene coating to the metal body sheet during normal cooking and cleaning conditions. Any separation or rupture of the polytetrafluoroethylene coating with respect to the underlying steel body sheet exposes the steel body sheet to the corrosive action of acids, bases and other corrosive chemicals in foods, and to water during the cleansing process, which contact causes corrosion and rusting of the underlying steel body sheet. Such rusting of the steel body sheet through the polytetrafluoroethylene layer is both unsightly and unsanitary and was found to be highly undesirable by users of the cooking utensile.
Efforts have been made to overcome this problem of the rupture of the polytetrafluoroethylene coating and the rusting of the steel body sheet thereunder by substituting other materials for the steel body sheet, which other materials are less subject to corrosion and rusting. For example, certain manufacturers have made the body sheet of aluminum, while others have provided an aluminized steel body sheet as is illustrated in U.S. Pat. No. 3,241,545 granted Mar. 22, 1966 to R. L. Reinert and C. T. Fliss. Such constructions are substantially more expensive than body sheets formed of steel and difficulty is sometimes encountered in providing good adherence of the polytetrafluoroethylene coating to the body sheet.